Effects of Timber Harvest following Wildfire in Western North America
David L. Peterson et al.
(Manuscript in review)
Timber harvest following wildfire leads to different outcomes depending on the biophysical
setting of the forest, pattern of burn severity, operational aspects of tree removal, and other
management activities. Fire effects range from relatively minor, in which fire burns through the
understory and may kill a few trees, to severe, in which fire kills most trees and removes much of
the organic soil layer. Post-fire logging adds to these effects by removing standing dead trees
(snags) and disturbing the soil. The influence of post-fire logging depends on the intensity of the
fire, intensity of the logging operation, and management activities such as fuel treatments. In
severely burned forest, timing of logging following fire (same season as fire vs. subsequent
years) can influence the magnitude of effects on naturally regenerating trees, soils, and
commercial wood value. Removal of snags reduces long-term fuel loads but generally results in
increased amounts of fine fuels for the first few years after logging unless surface fuels are
effectively treated. By reducing evapotranspiration, disturbing the soil organic horizon, and
creating hydrophobic soils in some cases, fire can cause large increases in surface-water runoff,
stream flow, and erosion. Through soil disturbance, especially the construction of roads, logging
with ground-based equipment and cable yarding can exacerbate this effect, increasing erosion
and altering hydrological function at the local scale. Effects of removing trees on aquatic
systems are mostly negative, and logging and transportation systems that disturb the soil surface
or accelerate road-related erosion can be particularly harmful unless disturbances are mitigated.
Cavity-nesting birds, small mammals, and amphibians may be affected by harvest of standing
dead and live trees, with negative effects on most species but positive or neutral effects on other
species, depending on the intensity and extent of logging. Data gaps on post-fire logging include
the effects of various intensities of logging, patch size of harvest relative to fire size, and longterm (10+ yr) biophysical changes. Uncertainty about the effects of post-fire logging can be
reduced by implementing management experiments to document long-term changes in natural
resources at different spatial scales.